Recently, according to technologies that are being developed so rapidly, high-performance, light-weight, thin, short, and small electronic apparatuses have been appearing and commercialized in the market.
If such electronic apparatuses do not radiate heat generated in the inside thereof, over-accumulation of heat may cause generation of an afterimage on a screen, disorders of a system, a reduced life span of a product, and the like, and may provide a source of explosion and fire in severe cases.
In particular, mobile terminals such as cellular phones (smartphones) are required to have a small-size and a light-weight, in order to maximize user's portability and convenience, and integrated components are being gradually mounted in a small space to meet high-performance. Accordingly, components used in mobile terminals may heighten a heat-generating temperature to obtain high-performance, and the heightened heat-generating temperature may have an effect on adjacent components to thus degrade performance of the mobile terminals.
Meanwhile, mobile terminals such as mobile phones are mostly used in a state in contact with a user's face, and thus heat generated in the mobile terminals is delivered to the user's skin to cause a problem of resulting in a low-temperature burn which may damage the protein in the user's skin. As a result, it is necessary to reduce the heat transferred out of the mobile terminals at a predetermined temperature or lower.
A variety of materials have been employed to solve the problem caused by heat generation of the mobile terminals, but an optimal material whose thickness is thin and having excellent heat-radiating performance has yet to be developed. Thus, the research and technology development thereof is urgent.
Meanwhile, Korean Patent Application Publication No. 10-2014-0029159 discloses a heat-radiating adhesive sheet of a foam type for use in smartphones and tablet PCs, in which the heat-radiating adhesive sheet includes a foaming layer, and adhesive layers that are formed on top and bottom surfaces of the foaming layer.
However, the heat-radiating adhesive sheet includes a foaming layer of a polyolefin-based, urethane-based, and acrylic-based material, and has a limit in radiating high-temperature heat locally generated from hotspot heat-generating components of mobile terminals. The adhesive layers also degrade heat-radiating efficiency and thus may not solve the problem of heat generation in recent high-performance mobile terminals.